Updated 2 November 2026 · By Diego Gómez

Condensation on windows every morning: causes and fixes

Why your windows are wet every morning in winter, whether it's a problem, and how to stop condensation with ventilation, heating and a dehumidifier.

Streaming windows on a winter morning are condensation: warm, moist air from breathing, cooking, showers and drying clothes meets the cold glass and turns back into water.

Is it a problem?

A little on single glazing on a frosty morning is normal. Pools of water on the sill every day, black spots on the seals or frames, or condensation on walls too, mean the air inside is too humid and mould will follow.

How to stop it

  1. Wipe the windows every morning with a squeegee or cloth so the water doesn't soak into frames and walls.
  2. Open the trickle vents at the top of modern windows and leave them open.
  3. Ventilate for 10 minutes in the morning with the window wide open.
  4. Keep bedroom doors open at night or crack a window: two people breathe out a surprising amount of moisture overnight.
  5. Run a dehumidifier in the worst room, set to around 50–55%. A 12-litre compressor model is enough for most bedrooms and flats.

Recommended

Best for most homes

Pro Breeze OmniDry 12L

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  • up to 15 m²
  • 2 L

The best-selling dehumidifier on Amazon UK right now: 12 litres a day, automatic humidity sensor, laundry mode and a drain hose option.

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For cold rooms

EcoAir DD2 Simple (desiccant)

  • 9 L/day
  • 1 °C
  • 3 L

A light desiccant dehumidifier that keeps working in cold, unheated rooms down to 1 °C, where compressor models struggle.

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Measure first

ThermoPro TP49 hygrometer (4-pack)

  • temperature and humidity
  • 4
  • AAA

Cheap digital hygrometers with a comfort-level face.

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FAQs

Will a dehumidifier stop window condensation?

Usually yes. Bringing the room below about 55% relative humidity means far less moisture reaches the glass. On very cold nights you may still see a little on the edges.

Do I need double glazing?

It helps because the inner pane is warmer, but double-glazed windows still get condensation if the air indoors is very humid.

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